Vinagre 3.9.5 Implements New APIs

Vinagre 3.9.5 fixes credential access with libsecret, improves credential description, fixes a logic bug in utils.show_many_errors(), adds the recognize_file() API to VinagreProtocol interface, and uses the new recognize_file() API for parsing files. Moreover, Vinagre 3.9.5 implements the recognize_file() API in VNC plugin and the recognize_file() API in SPICE plugin, makes the BookmarksTree widget smaller, and fills the right IPv6 notation when using the Avahi dialog.